34 entries under proof topic. ×

11
tight(adjective, close, solid, short, substantial)
8
hermetic(adjective, tight, impervious, impenetrable)
8
waterproof(adjective, water, tight, impervious)
7
sealed(adjective, tight, impervious, impenetrable)
7
watertight(adjective, tight, impervious, impenetrable)
6
airtight(adjective, tight, impervious, impenetrable)
3
pressure-tight(adjective, tight, impervious, hermetic)
2
air-tight(adjective, tight, impervious, hermetic)
2
resistant(adjective, unaffected, unyielding, unbending)
2
retentive(adjective, tight, impervious, hermetic)
2
water-tight(adjective, tight, impervious, hermetic)
1
air-locked(adjective, tight, impervious, hermetic)
1
air-proof(adjective, tight, impervious, hermetic)
1
airproof(adjective, tight, impervious, hermetic)
1
dampproof(adjective, tight, impervious, hermetic)
1
enclosed(adjective, tight, impervious, hermetic)
1
gas-tight(adjective, tight, impervious, hermetic)
1
gas proof(adjective, tight, impervious, hermetic)
1
gastight(adjective, tight, impervious, hermetic)
1
hermetical(adjective, tight, impervious, hermetic)
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APASmart Define. (2015). impermeable thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/impermeable/thesaurus/synonyms
ChicagoSmart Define. 2015. "impermeable thesaurus" https://smartdefine.org/impermeable/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2015, impermeable thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/impermeable/thesaurus/synonyms>.
MLASmart Define. "impermeable thesaurus" 14 April 2015. Web. 22 September 2026. <https://smartdefine.org/impermeable/thesaurus/synonyms>